1. Field of the Invention
The present invention relates to an engine-driven operating machine that uses an engine to drive an electric generator, a compressor, a pump, and the like, and in particular, relates to an engine-driven operating machine that has been made soundproof.
2. Description of the Related Art
This type of engine-driven operating machine is installed on a base, forming a foundation, and is housed in a soundproof case. The soundproof engine-driven operating machine should preferably have a small installation area and a simple structure, while being easy to assemble and disassemble and having superior soundproofing characteristics.
FIGS. 11 and 12 show an example of this type of engine-driven operating machine. In this example, disclosed in Laid-open Japanese Patent Application No. 1996-261008, an air-cooled engine E and a generator G, that is connected to the engine E by a belt 214, are installed via rubber isolators 215 on a bearing plate 212, provided on a mounting board 206.
An inside case 202 is fitted on the mounting board 206 with rubber isolators 207 in between. Rubber isolators 208 are affixed to the top face of a ceiling plate 204 of the inside case 202, and an outside case 203 is fitted outside them. Bottom ends of the outside case 203 are secured to securing tools 216, that are secured to the mounting board 206 by tightening screws 217.
This obtains a double-layer case 201 having inside and outside cases, that shut off noise generated by internal devices. Sound transmission between the inside case 202 and the outside case 203 is thereby prevented.
FIG. 13 shows another conventional constitution. This constitution is disclosed in Laid-open Japanese Patent Application No. 2002-4857, and includes an assemble-type soundproof case. The framework of a soundproof case K includes a front frame 321, a rear frame 331, and an unillustrated center frame, that are assembled on a base.
The inside of the soundproof case K is partitioned into an engine chamber 301, a muffler chamber 302, and a radiator chamber 303. The engine chamber 301 contains an engine E and a operating machine main body G, the muffler chamber 302 contains a muffler, and the radiator chamber 303 contains an unillustrated radiator. A plurality of unillustrated wind outlet holes are provided in the side walls of the radiator chamber 303, a wind inlet hole is provided in the muffler chamber 302, and the muffler chamber 302 and the radiator chamber 303 are joined together.
In this constitution, cooling wind that cools the engine chamber 301 is sucked in from wind inlet holes 331a and 335a by an axle-driven engine fan. After cooling the inside of the engine chamber 301, the cooling wind passes through the engine fan and cools an unillustrated intercooler, passes via a ventilation duct 304 to the muffler chambers 302A and 302B, where it cools the muffler and is then discharged into the atmosphere.
An unillustrated wind inlet hole is formed in the front left side wall (as viewed in FIG. 8) of the radiator chamber 303 inside the front frame 321, the radiator being provided on a wall face opposite the wind inlet hole. An electrically powered fan faces the radiator between the wind inlet hole and the radiator, and fans the cooling wind into the muffler chamber 302B.
The electrically powered fan sends the cooling wind through a special spherical wind hole, formed in the radiator chamber 303. After cooling the radiator, the cooling wind is sent into the muffler chamber 302B and discharged into the atmosphere from a wind outlet hole, formed in the ceiling of the muffler chamber 302B.
The conventional example shown in FIG. 8 is disclosed as a soundproof case having a low-noise structure that increases cooling efficiency by arranging separate heat exchangers along the path of the cooling wind.
Although the conventional example shown in FIGS. 6 and 7 has superior soundproofing effects, the two cases must be removed in order to inspect the inside, which is troublesome. The structure becomes particularly complex and unsuitable for miniaturization in the case of large-scale device or the like, or a case where the apparatus required for operation is installed outside the engine or the operating machine main body.
The conventional example shown in FIG. 8 succeeds in providing a engine-driven operating machine that is quiet and has good cooling capability, but its length is difficult to shorten since the operating machine main body, the engine, the engine fan, the intercooler, and the cooling duct, are arranged in a straight line. Since the soundproof case is a collective body formed by joining primary members, its structure is complex and expensive, and it is time-consuming to assemble and disassemble.